Four-high rolling mill



March 7, 1967 F. w. A. WARD ETAL 3,307,386

YFOUR-HIGHROLLING MILL 5 Sheets-Sheet 1 Filed July 15, 1963 QM TA W VK NM JAMES DOUGLAS BY I " A TTORNEYS.

March 7, 1967 FOUR-HIGH ROLLING MILL Filed July 15, 1963 F. W. A. WARD ETAL 5 Sheets-Sheet 2 FIG. 4

INVEN TORS FREDERICK W A. WARD JAMES DOUGLAS ATTORNEYS.

- March 1967 w. A. WAR D 'ETAL 3,307,386

FOUR-HIGH ROLLING MILL 3 Sheets-Sheet 5 Filed July 15, 1965 irl 0 M s U W W m WW m NCS T Efl A EM w R F United States Patent ()ffice 3,307,386 Patented Mara-7, 1967 This invention relates to the design of housing for use in connection with four-high rolling mills.

Conventional four-high rolling mill designs use housings having elongated, :generally rectangular shaped windows of a width adapted to accommodate the upper and lower back-up roll chocks. These chocks are in turn formed with legs disposed on the mutually facing surfaces thereof. Within the spaces defined by these legs are disposed the upper and lower work roll chocks, adapted to slide up and down against bearing surfaces provided by the legs of the back-up chocks themselves. In order to provide roll balance it is accepted design practice to dispose a set of hydraulic cylinders and pistons in each lower back-up roll chock in order to set the upper back-up roll chock against the screw. Another set of hydraulic cylinders and pistons is usually disposed between the work roll chocks.

A conventional arrangement of the type discussed above exhibits a number of disadvantages. In the first place, and as will be apparent from the description given, the accuracy of alignment of the work rolls depends on the clearances associated with four sliding surfaces, each of which is subject to substantial wear. Secondly, the profile of the back-up roll chocks, characterized as it is by the provision of legs which will accommodate the work roll chocks, is relatively complicated and therefore expensive to machine. Thirdly, the relationship between the chocks is such that, in order to remove the bottom backup roll in the event of damage thereto, it is necessary as well to remove all of the other rolls and chocks in the mill. Fourthly, in some designs it is necessary, in order to accommodate the required hydraulic apparatus, to have the profiles of the work roll chocks different; this in itself prohibits interchangeability and requires a greater stock of work roll assemblies to be kept on hand for any given mill. Fifthly, further disadvantages of conventional de sign result from the fact that all of the cylinders in the hydraulic circuit are disposed within the chocks them selves. This complicates and renders relatively expensive the manufacture of the chocks and, since the cylinders are disposed in the chocks rather than in the housing, many more of them must be provided for any given machine, thus increasing both capital and maintenance costs. Moreover, since the connections between the cylinders and the other parts of the hydraulic circuit must be broken whenever roll change is desired, the conventional arrangement substantially increases the down-time involved in such operations.

Finally, the conventional housing design, as discussed above, imposes severe limitations upon the extent to which contour control may be exercised during operation of the mill. During the last few years techniques have been developed, within the framework of conevntional fourhigh rolling mill design, to utilize the work roll balance system disposed between the work roll chocks to effect some degree of contour control by flexing the Work rolls against the back-ups. Another well known and conventional construction involves the disposition, between the backup roll chocks and their associated work roll chocks, of hydraulic cylinder-piston assemblies which permit flexure of the work rolls in the opposite direction.-

Because both these methods depend upon actuation of hydraulic apparatus located entirely within the chocks themselves, the results obtained are severelylimited by the range of stability of the chock system. So far as concernsflexure of the work rolls against the back-up rolls, it is not possible with conventional arrangements to control the flexure of one of the work rolls independently of the other, since the flexure in question is brought about by hydraulic cylinder and piston arrangements working directly between the relevant chocks.

We have found that the disadvantages of conventional four-high rolling mill designs discussed above can be substantially overcome and appreciable advantages gained;

tween the upper surface of the flange, and the lower sur-- face of the upper back-up roll chock, are further hydraulic cylinder-piston arrangements which provide upper back-..

up roll balance. In another prefered embodiment of our invention we provide work roll chocks having outwardly extending lugs at the base thereof.- A groove is dis posed in the mutually facing surfaces of each of the flanges so as to accommodate the lugs of the top work roll chocks, the lugs of the bottom work roll chocks being With this arrange-.

accommodated beneath the flanges. ment contour control apparatus is disposed within the flanges and adapted to transmit forces between the flanges and the lugs of each of the work roll chocks. In both these embodiments of our invention the work roll chocks have sliding engagement with the housing directly, with the result that their stability is determined by only two sliding surfaces and it is possible by known means to eliminate substantially completely the effects of play caused by this residual clearance by the addition of side. thrust cylinder and piston arangements now in use on some commercially available machines. In the case of the second preferred embodiment of our invention, a further substantial advantage results since, in that case, all of the hydraulic cylinders can be disposed in the housing itself, rather than in the chocks, with the resulting substantial simplication of chock design, removal, maintenance and cost. In both embodiments of the invention it is possible to remove the lower back-up roll without disturbing the upper back-up roll. In the case of the preferred embodiment of the invention, this operation does not require the removal of either the upper back-up roll or upper work roll. Similarly, removal of the chocks and rolls from the housing will not require disconnection of hydraulic circuitry, thus substantially reducing down-time. Further advantages result from the fact that in both embodiments of the invention the top and bottom work roll assemblies are interchangeable. the fact that, in the preferred embodiment of our invention, all of the hydraulic cylinders are disposed in the housing itself, it is possible to efiect independent control,

of the flexure of the work rolls in the direction towards their corresponding back-up rolls.

Our invention will be described in connection with the following figures of drawings in which:

FIG. 1, shows in elevation the front face of one housing of a four high rolling mill with the back up and work roll chocks therein shown in cross section to better illustrate the construction of the latter.

FIGURE 2 is a sectional view through the lower work roll chock, along the lines 2-2 of FIGURE 1;

Finally, as a result of FIGURE 3 is a pictorial view, partly in section, of a four-high rolling mill, similar to that shown in FIG. 1, incorporating the preferred embodiment of our invention; and

FIGURE 4 is an enlarged sectional view of a four-high rolling mill of the type shown in FIGURE 3 taken on lines IVIV, illustrating particularly the region thereof adjacent the work roll chocks.

Referring to the drawings, the housings 1 on each side of a four-high rolling mill support at each end upper and lower back-up rolls 2 and 3 upper and lower work rolls 4 and 5 each end of these rolls being journaled by conventional means in upper and lower back-up roll chocks 6 and 7, and upper and lower work roll chocks 8 and 9, respectively.

It will be observed that in each case the housing 1 is provided with an aperture generally represented at 10 which itself comprises upper and lower generally rectangularly shaped windows 11 and 12, adapted to accommodate the back-up roll chocks 2 and 3, respectively. The aperture 10 also includes a slot generally indicated 13, extending between the windows 11 and 12, the sides of this slot being defined by the mutually facing surfaces 14 and 15 of two inwardly extending flanges 16 and 17, respectively, which, in effect, separate the windows. In the embodiment of the invention illustrated in FIGURES 1 and 2, the mutually facing surfaces of these flanges 16 and 17, are straight and are adapted to engage directly with the work roll chocks 8 and 9 if desired through aside thrust arrangement, comprising hydraulic cylinders '20 and 21, disposed along one side of each of the chocks shown in FIGURE 1. As shown in FIGURES 1 and 2, the chocks accommodate a plurality of hydraulic cylinderpiston arrangements which, in accordance with known principles, may be actuated to effect the work roll balance and contour control during the operation of the mill. In order to ensure the constant availability of a work roll balance force, it may be desirable to dispose the hydraulic cylinder-piston arrangements within the work roll chocks as shown in FIGURE 2 wherein work roll balance is provided by the center pistons 25 and 26, and contour control can, within the limitations of this arrangement, be effected by the pairs of pistons 27 and 28 disposed on each side of the roll balance pistons 25 and 26. With this arrangement it is possible, by actuation of pistons 27 and 28 disposed in the lower work roll chock 9 downward and upward flexure of the ends of the upper work roll 4 to effect flexure of the ends of the lower work roll 5. Similarly, by actuation of the pistons 29 and 30, disposed within the upper work roll chock 8, it is possible to flex the upper work roll 4 by downward displacement of its ends. As shown :in the drawing, upper back-up roll balance cylinder piston units 31 are disposed in the upper back-up roll chock 6, with the pistons thereof adapted to bear on the upper surfaces 32 of the flanges 16 and 17.

While the embodiment of the invention discussed in connection with FIGURES 1 and 2 does not provide all of the contour control features which are made available by the preferred embodiment of the invention, to be discussed below, it is apparent from FIGURE 1 that substantial advantages over conventional arrangements are obtained from the design there shown. In particular, it will be noted that each of the chocks bears directly against surfaces of the housing itself with the resulting increase in rigidity and accuracy of the mill. Moreover,

the cross-sections of the back-up roll chocks are considerably simpler than conventional designs and are, accordingly, less expensive to manufacture. The top and bottom work roll chocks can moreover, be made identical with the result that less spares must be kept on hand for use in association with any given mill. Finally, it will be noted that the bottom back-up r-oll may be removed without disturbing the top back-up roll, thus resulting in a substantial saving of down-time when this operation m e at s ed Referring now to the preferred embodiment of the invention illustrated in FIGURES 3 and 4, it will be observed that the aperture 10 of .the housing 1 is similar to that shown in FIGURES 1 and 2, except that a groove 35 is dispose-d in the surfaces 14, 15 of the flanges 16, 17, about the middle thereof, thus dividing each flange into upper portions 36 and lower portions 37 as shown. With this arrangement both the upper and lower work roll chocks 8, 9 are provided with lugs 38 which extend outwardly from each side of the base thereof. The lugs 38 of the upper work roll chock 8 are accommodated in the groove 35, whereas the lugs 38 of the lower work roll chock 9 are accommodated below the flanges 16, 17, as shown. Mounted within the lower portions 37 of the flanges 16, 17 are hydraulic units, 40, 41, 42 and 43. Units 40 and 41 are disposed in the lower surfaces of the flanges 16 and 17 so that the pistons thereof engage with the upper surfaces of the lugs 38 of the lower work roll chock. The units 42 and 43 are disposed in the upper surface of the same lower portions 37 of the flanges 16, 17 so that the pistons thereof engage with the lower surface of the lugs 38 of the upper work roll chock. 'Further hydraulic units 45 and 46 are disposed in the lower surface of the upper portion 36 of the flanges 16, 17 so that the pistons thereof are capable of engaging with the upper surface of the lugs 38 of the upper work roll chock. Finally, in order to provide the required upper back-up roll balance, hydraulic units 47 and 48 are disposed in the upper portions 36 of the flanges 16, 17, so that the pistons thereof are capable of engaging with the lower surface of the upper back-up roll chocks, as shown. In the drawings only one hydraulic unit is shown in each of the positions described; as will be apparent to persons skilled in the art it will be possible (as was illustrated in FIGURE 2 in connection with the embodiment shown in FIGURE 1) to dispose a plurality of hydraulic units operating in parallel with each other.

With the arrangement shown in connection with FIG- URES 3 and 4, greatly improved contour control can be effected. If for instance the draft on the mill is too light, pressure on the units 45 and 46 will push down the top work roll chock so as to make the required correction. If, on the other hand, the draft is too heavy, the pressure on the units 42 and 43 will push upward on the top work roll chock so as to make the required reverse correction. The units 40 and 41 are used mainly to maintain pressure between the bottom work roll and the bottom back-up roll in order to prevent slippage between the rolls in the event of their coming directly into contact with each other. The units 47 and 48 are usedto separate ,the top back-up roll from the top work roll during a work roll change in the mill.

With the preferred embodiment of our invention it will be apparent that a number of substantial advantages have been obtained. In the first place, the profile of the backup roll chocks has been greatly simplified since no legs are necessary. Secondly, hydraulic cylinders have been eliminated from all of the chocks. This greatly facilitates removal of the chocks since it is not necessary to break the hydraulic connections when this is done. It is, moreover, possible to apply directly the required slide lubrication to the work roll chocks, as well as the back-up roll chocks. It will be apparent, moreover, from FIGURES 3 and 4 that it is possible to remove the bottom back-up roll assembly without first removing either the top work roll or the top back up roll assemblies. Finally, the top and bottom work roll chocks are interchangeable, thus reducing the spare parts required. All these advantages are accompanied with the obtaining of a simpler and stiffer mill, together with improved contour control facilities.

We claim:

1. A four high rolling mill comprising: a housing having upper and lower generally rectangularly shaped windows and a slot extending therebetween, said slot being defined by the mutually facing surfaces of two inwardly extending flanges separating the windows; upper and lower back-up .roll chocks disposed respectively in said upper and lower windows, and adapted to sliding engagement therewith; upper and lower work roll chocks disposed within said slot and adapted to have sliding engagement With said surfaces; and contour control apparatus for selectively applying pressure to at least said work roll chocks and said upper back-up roll chock.

2. A four high rolling mill as defined in claim 1 wherein said contour control apparatus comprises: hydraulically actuated pistons extending upwardly from said lower and upper work roll chocks and adapted respectively for engagementwith said upper work roll chocks and said upper back-up roll chocks; and further hydraulically actuated pistons extending downwardly from said upper back-up roll chock and adapted for engagement with the upper surfaces of said flange.

3. A four high rolling mill as defined in claim 1 wherein said housing includes a groove centrally located in each of said surfaces and said upper work roll chock has lugs extending outwardly from the base thereof into each of said grooves.

4. A four high rolling mill as defined in claim 3 wherein said contour control apparatus includes hydraulically actuated pistons extending upwardly and downwardlly from the sides of said groove and adapted for engagement with the upper end lower surfaces of said lugs.

5. A four high rolling mill as defined in claim 4 wherein said lower work roll chock also has lugs extending outwardly from the bottom thereof and said contour control apparatus also includes hydraulically actuated pistons extending downwardly from the lower surface of said flange for engagement with said last mentioned lugs.

6. A four high rolling mill as defined in claim 5 including further hydraulically actuated pistons extending upwardly from the upper surfaces of said flange and into engagement with said upper back-up roll chock.

7. A housing for a four high rolling mill having upper and lower generally rectangularly shaped windows adapted to accommodate back-up roll chocks, and a slot extending between said windows, said slot =being defined by the mutually facing surfaces of two inwardly extending flanges separating the windows and being adapted to accommodate work roll chocks having sliding engagement therewith; and a groove located in the mutually facing surfaces of each of said flanges, said groove adapted to accommodate a top work roll chock having outwardly extending lugs at the bottom thereof.

8. A housing as defined in claim 7 including hydraulic means disposed in said flanges for controlling the position of the work roll chocks.

9. A housing as defined in claim 8 wherein said hydraulic means is adapted to effect contour control.

10. A housing as defined in claim 9 wherein said hydraulic means consists of cylinder and piston assemblies disposed within said flanges in opposing relation on opposite sides of said groove, whereby both upward and downward pressure can be applied to said lugs.

11. A housing as defined in claim 8 wherein said hydraulic means consists of cylinder and piston assemblies disposed within said flanges in opposing relation on opposite sides of said groove, whereby both upward and downward pressure can be applied to said lugs, and further cylinder and piston assemblies disposed within said flanges so as to project from the bottom surface whereby downward pressure can be applied to a lower work roll chock having outwardly extending lugs at the bottom thereof.

12. A four high rolling mill which includes a housing having upper and lower generally rectangularly shaped windows and a slot extending there between, said slot being defined by the mutually facing surfaces of two inwardly extending flanges separating the windows; upper and lower back-up roll chocks having sliding engagement with the sides of said upper and lower windows respectively; upper and lower work roll chocks having sliding engagement with said mutually facing surfaces of said flanges; a groove located in the mutually facing surfaces of each said flanges; and said upper work roll chock having outwardly extending lugs at the bottom thereof extending into said grooves.

References Cited by the Examiner UNITED STATES PATENTS 1,655,063 1/ 1928 Kriwan 72242 1,935,091 11/ 1933 Iversen 72243 2,056,433 10/ 1936 Matthews 72243 2,095,448 10/ 1937 McBane 72243 2,430,410 11/ 1947 Pauls 72243 3,204,443 9/ 1965 Kalberkamp 72-239 CHARLES W. LANHAM, Primary Examiner.

C. H. HITTSON, R. J. HERBST, Assistant Examiner. 

1. A FOUR HIGH ROLLING MILL COMPRISING: A HOUSING HAVING UPPER AND LOWER GENERALLY RECTANGULARLY SHAPED WINDOWS AND A SLOT EXTENDING THEREBETWEEN, SAID SLOT BEING DEFINED BY THE MUTUALLY FACING SURFACES OF TWO INWARDLY EXTENDING FLANGES SEPARATING THE WINDOWS; UPPER AND LOWER BACK-UP ROLL CHOCKS DISPOSED RESPECTIVELY IN SAID UPPER AND LOWER WINDOWS, AND ADAPTED TO SLIDING ENGAGEMENT THEREWITH; UPPER AND LOWER WORK ROLL CHOCKS DISPOSED WITHIN SAID SLOT AND ADAPTED TO HAVE SLIDING ENGAGEMENT WITH SAID SURFACES; AND CONTOUR CONTROL APPARATUS FOR SELECTIVELY APPLYING PRESSURE TO AT LEAST SAID WORK ROLL CHOCKS AND SAID UPPER BACK-UP ROLL CHOCK. 